Field of the Invention
The present invention relates to an organic light emitting display with improved viewing angle and lifespan.
Discussion of the Related Art
The recent advent of information-dependent age has brought about rapid development in the display field that visually displays electrical information signals. In this regard, a variety of flat panel displays having superior properties such as slimness, low weight and low power consumption have been developed.
Examples of flat panel displays include liquid crystal displays (LCDs), plasma display panels (PDPs), field emission displays (FEDs), organic light emitting displays (OLEDs), and the like.
In particular, an organic light emitting display spontaneously emits light, which has the advantages of rapid response speed, superior luminous efficacy, excellent brightness and wide viewing angle, as compared to other flat panel displays. Such an organic light emitting display includes an anode and a cathode which face each other such that a light emitting layer is interposed therebetween. Holes injected from the anode recombine with electrons injected from the cathode in the light emitting layer to form electron-hole pairs, i.e., excitons. Upon an exciton's transition to a ground state, energy is released. Based on this energy, the organic light emitting display emits light. The light emitting layer of conventional organic light emitting displays is formed by co-depositing a host with a dopant. However, when a doping concentration is not uniform in the light emitting layer composed of the host and the dopant, an undoped host causes light emission, thus disadvantageously deteriorating viewing angle and lifespan. Specifically, as shown in FIG. 1, in a case in which the viewing angle is zero degrees, when the light emitting layer is uniformly doped, it has one luminescent peak. On the other hand, when the light emitting layer is non-uniformly doped, it has two luminescent peaks. Accordingly, when the light emitting layer is non-uniformly doped, in the case in which the viewing angle is zero degrees, colors corresponding to the two luminescent peaks appear to be mixed and color reliability according to viewing angle is disadvantageously deteriorated.